Explain · Like I'm five version
Why the sky is blue in terms of a football crowd
Why is the sky blue instead of another colour?
The sky is a big crowd at a football match, and the sunlight is the light from the stadium lamps. When the light shines down, it hits all the tiny bits of air in the atmosphere like the crowd in the stands. Blue light is very bouncy and fast, so it hits these little bits of air and bounces off in every direction like a ball being kicked around the pitch. The other colours are lazy and walk straight through the crowd without stopping to play.
Because the blue light is bouncing everywhere, it reaches your eyes no matter where you look up. It is like when the crowd gets really excited and starts cheering, so you hear the noise coming from all sides of the stadium at once. You see that lovely blue glow all over the sky because those blue light particles have had a brilliant time jumping around, while the red and yellow light particles just went straight out the back exit without seeing any of the fun.
When the sun is low near the horizon, the light has to travel through a much bigger crowd to reach you. By the time it gets to your seat, all the blue light has been kicked away to other parts of the sky, leaving only the tired red and orange light to reach your eyes. This is why sunsets look like a nice cup of tea, while the daytime sky looks like a bright blue football shirt.
Where the analogy breaks downAir molecules are not people and they do not have feelings or teams.